CODEWITHSUNDEEP
perlipv6
Bash
Bash

Reputation: 1

Perl Convert Long IPv6 Address To Compact Notation

I have a long IPv6 address in a scalar like 

2001:0db8:0:0:0:0:0:0

and would like to get the compact notation:

2001:db8::.

Does the main Perl package /usr/lib/perl5/... contain a module that will do this?

Does the Net::IP module?

If not, does someone have a few lines that would do this?

Sort of the opposite of what Net::IP::ip_expand_address does.

Upvotes: 0

Views: 979

Answers (3)

Bash
Bash

Reputation: 1

Net::IP indeed offers the ip_compress_address method to compress an IP.

Upvotes: 0

bytepusher
bytepusher

Reputation: 1578

The NetAddr::IP module offers the short method to do just that.

example:

#!/usr/bin/env perl
use strict;
use warnings;
use NetAddr::IP;

my $ip = NetAddr::IP->new( '2001:0db8:0:0:0:0:0:0' );

print "Long version: " . $ip->addr . "\n";
print "Short/Compact version: " . $ip->short . "\n";

Upvotes: 2

simbabque
simbabque

Reputation: 54371

The module IPv6::Address can do that when you call its addr_string method, but it's not in core. However, you can borrow the code that does it fairly quickly.

All I did was take the part that creates the compact notation, and wrap it in a sub.

sub compact {

    # taken from IPv6::Address on CPAN
    my $str = shift;
    return '::' if($str eq '0:0:0:0:0:0:0:0');
    for(my $i=7;$i>1;$i--) {
            my $zerostr = join(':',split('','0'x$i));
            ###print "DEBUG: $str $zerostr \n";
            if($str =~ /:$zerostr$/) {
                    $str =~ s/:$zerostr$/::/;
                    return $str;
            }
            elsif ($str =~ /:$zerostr:/) {
                    $str =~ s/:$zerostr:/::/;
                    return $str;
            }
            elsif ($str =~ /^$zerostr:/) {
                    $str =~ s/^$zerostr:/::/;
                    return $str;
            }
    }
    return $str;
}


print compact('2001:0db8:0:0:0:0:0:0');

This will print

2001:0db8::

It seems to be ok with already compacted strings too.

Upvotes: 0

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